Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 21
Filtrar
Más filtros











Base de datos
Intervalo de año de publicación
1.
Insects ; 15(8)2024 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-39194820

RESUMEN

Increasing temperature can enhance the geographical spread and behavior of disease vector mosquitoes, exposing vulnerable populations to Aedes-borne viruses and infections. To address this risk, cost-effective and sustained intervention vector control tools are required, such as volatile pyrethroid spatial repellents. This study used a high-throughput screening system toxicity bioassay to determine the discriminating concentrations of transfluthrin-treated filter papers with variable air-drying times exposed to pyrethroid-susceptible Aedes aegypti mosquitoes. At the highest transfluthrin concentration (0.01706%), a significant reduction in mosquito mortality was observed in filter papers air-dried for 24 h compared to those air-dried for 1 h (odds ratio = 0.390, p < 0.001, 95% confidence interval: 0.23-0.66). Conversely, no significant difference in mortality was found between filter papers air-dried for 1 h and those air-dried for 12 h (odds ratio = 0.646, p = 0.107, 95% confidence interval: 0.38-1.10). The discriminating concentration was 2.8-fold higher for transfluthrin-treated filter papers air-dried for 24 h than it was for papers air-dried for 1 h, and it increased 5-fold from 1 h to 336 h of air-drying. These results show that the optimal air-drying period of transfluthrin-treated filter paper is critical, as higher discriminating concentration values may lead to underestimations of insecticide resistance. The instability of transfluthrin-treated papers necessitates the use of the World Health Organization (WHO) bottle bioassay, which is the preferred method for determining mosquito susceptibility to volatile insecticides.

2.
Adv Sci (Weinh) ; 11(29): e2309467, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38626368

RESUMEN

Spin-transfer torque (STT) and spin-orbit torque (SOT) form the core of spintronics, allowing for the control of magnetization through electric currents. While the sign of SOT can be manipulated through material and structural engineering, it is conventionally understood that STT lacks a degree of freedom in its sign. However, this study presents the first demonstration of manipulating the STT sign by engineering heavy metals adjacent to magnetic materials in magnetic heterostructures. Spin torques are quantified through magnetic domain-wall speed measurements, and subsequently, both STT and SOT are systematically extracted from these measurements. The results unequivocally show that the sign of STT can be either positive or negative, depending on the materials adjacent to the magnetic layers. Specifically, Pd/Co/Pd films exhibit positive STT, while Pt/Co/Pt films manifest negative STT. First-principle calculations further confirm that the sign reversal of STT originates from the sign reversal of spin polarization of conduction electrons.

3.
Insects ; 14(9)2023 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-37754735

RESUMEN

Aedes aegypti is a major vector of dengue fever in tropical regions. Spatial repellents (SRs) have shown promise in delaying pesticide resistance. Methods for discriminating concentrations (DCs) are well established using various bioassay tools, while data for high-throughput screening system (HITSS) toxicity bioassay (TOX) are absent. In this study, we compared and optimized lethal (LCs) and sub-lethal concentrations (SLCs) of transfluthrin (TFT) and metofluthrin (MFT) on pyrethroid-susceptible (USDA) and pyrethroid-resistant (Pu-Teuy) Ae. aegypti (L.) strains, using the HITSS-TOX. Mean mortality (MT) was 100% at LC99 and DC, compared to LC50 (45.0 ± 3.7%) and LC75 (65.8 ± 7.0%) for the USDA strain. However, the resistant strain (Pu-Teuy) showed reduced susceptibility against TFT and a significantly lower MT at LC50 (12.5 ± 4.4%; t = 5.665, df = 10, p < 0.001), LC75 (9.2 ± 3.5%; t = 4.844, df = 10, p = 0.001), LC99 (55.0 ± 9.9%; t = 4.538, df = 5, p = 0.006), and DC (75.0 ± 5.2%; U = 3.0, p = 0.007). The DC of TFT (0.15222%) was 4.7-fold higher than for MFT (0.03242%) in USDA strain. The baseline DCs established are useful to better understand susceptibility and the efficacy of various repellents against field populations of Ae. aegypti.

4.
Sci Rep ; 12(1): 2307, 2022 Feb 10.
Artículo en Inglés | MEDLINE | ID: mdl-35145174

RESUMEN

Herein, we report an exotic domain-wall dynamics showing double Walker breakdowns in magnetic multilayer films composed of two magnetic layers. Such multiple Walker breakdowns are attributed to the internal magnetic dipole field, which is antisymmetric on the domain walls of the lower and upper magnetic layers. A micromagnetic simulation shows four phases of the domain-wall dynamics, which result in a phase diagram with the phase boundaries of the double Walker breakdown fields. Such double Walker breakdowns lead to two minima in the variation of the domain-wall velocity, as often observed experimentally.

5.
Parasit Vectors ; 14(1): 606, 2021 Dec 11.
Artículo en Inglés | MEDLINE | ID: mdl-34895318

RESUMEN

BACKGROUND: Entomological surveillance is an important means of assessing the efficacy of insect vector management programs and estimating disease transmission thresholds. Among baited traps, Biogents' BG-Sentinel (BGS) trap baited with BG-Lure is considered to have the most similar outcome to, and be a possible replacement for, human-landing catches for the epidemiologically relevant monitoring of adult Aedes aegypti and Culex quinquefasciatus. In contrast to the BGS trap, the Black Hole ultraviolet (UV) light trap, which is widely used to catch nocturnal flying insects, is not baited with synthetic human odor-mimicking lures. METHODS: We evaluated the L-lactic acid-based Kasetsart University (KU)-lures nos. 1-6 as novel candidate chemical lures for the diurnal species Ae. aegypti and the nocturnal species Cx. quinquefasciatus using two commercial traps (the BGS trap and the Black Hole UV light trap) in a semi-field screen (SFS) house. Firstly, we optimized the dose of each KU-lure in an SFS house (140 m3). Secondly, six different candidate KU-lures were screened by comparing their percent attraction using a single discriminating dose (0.5 g). Finally, we evaluated the synergism of the KU-lures selected in this way with commercially available traps. RESULTS: BGS traps baited with KU-lure no. 1 exhibited the greatest percent attraction for Ae. aegypti (29.5% ± 14.3%), whereas those baited with KU-lure no. 6 most strongly attracted Cx. quinquefasciatus (33.3% ± 10.7%). Interestingly, BGS traps treated with 10 g BG-Lure did not significantly attract more Ae. aegypti or Cx. quinquefasciatus than the untreated BGS traps. CO2 at a flow rate of 250 ml/min most strongly attracted both Ae. aegypti and Cx. quinquefasciatus (42.2% ± 14.2% and 75.1% ± 16.9%, respectively). BGS and Black Hole UV light traps with KU-lure no. 6 exhibited a stronger attraction for Cx. quinquefasciatus than untreated traps, and the percent attraction did not differ between the treated traps. CONCLUSIONS: Synergistic effects of KU-lures nos. 1 and 6 with the mosquito traps were demonstrated for both the diurnal and nocturnal species in the SFS house assays. However, further studies are urgently needed for the development of species-specific lures to increase trap efficacy in the field for local vector mosquitoes in Thailand.


Asunto(s)
Aedes/efectos de los fármacos , Anopheles/efectos de los fármacos , Culex/efectos de los fármacos , Ácido Láctico/farmacología , Mosquitos Vectores/efectos de los fármacos , Aedes/efectos de la radiación , Animales , Anopheles/efectos de la radiación , Culex/efectos de la radiación , Femenino , Humanos , Ácido Láctico/química , Masculino , Mosquitos Vectores/efectos de la radiación , Rayos Ultravioleta
6.
Insects ; 12(6)2021 Jun 06.
Artículo en Inglés | MEDLINE | ID: mdl-34204117

RESUMEN

Several types of olfactometers have been used to evaluate mosquito responses to agents that mimic natural volatiles that repel or attract. The Y-tube olfactometer has been widely used to study repellents and attractants, while the high-throughput screening system assay has only been used to study repellents. Whether the high-throughput screening system assay is suitable for evaluating attractants is unknown. We evaluated the responses to four lactic-acid-based mixtures and two non-lactic-acid-based chemical lure candidates using the high-throughput screening system (HITSS) for three mosquito species (laboratory strains and field populations of both Aedes aegypti (L.) and Culex quinquefasciatus Say.; laboratory strain of Anopheles minimus Theobald) under laboratory-controlled conditions. HITSS assay results showed that KU-lure #1 elicited the greatest percent attraction for pyrethroid-resistant and -susceptible Ae. aegypti. KU-lure #6 elicited the strongest attractive response for pyrethroid-susceptible and -resistant Cx. quinquefasciatus and pyrethroid-susceptible An. minimus. The response to the lures from each species was independent of the pyrethroid susceptibility status (Ae. aegypti, p = 0.825; Cx. quinquefasciatus, p = 0.056). However, a significant difference in attraction to KU-lure #6 was observed between diurnal and nocturnal mosquitoes (Cx. quinquefasciatus vs. Ae. aegypti, p = 0.014; An. minimus vs. Ae. aegypti, p = 0.001). The laboratory-level HITSS assay effectively selects potential lure candidates. Because the host-seeking behavior differs between mosquito species, further studies are needed to develop species-specific attractants. Additional studies in semi-field screen houses using commercial traps are necessary to evaluate the accuracy of these laboratory assay results.

7.
Insects ; 12(4)2021 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-33923471

RESUMEN

Natural volatile host cues play a critical role for mosquito orientation and locating a blood source for egg production. Similar olfactory activation responses have allowed the use and development of artificial chemical attractants to lure mosquitoes to trapping devices. Using a pre-formulated commercial product mixture of different attractant chemicals, a high-throughput screening system (HITSS) is used to screen varying doses of chemical required to activate behavioral responses. Two strains of Aedes aegypti (L.): permethrin-susceptible (USDA) and -resistant (Pu Teuy) phenotypes and one Culex quinquefasciatus Say. (NIH) laboratory strain were tested. Overall, mosquitoes showed repellency between 1.0 g and to 10.0 g dose of each compound. However, by progressively reducing the dose, Cx. quinquefasciatus showed a greater positive percent attraction (88.9%) at 0.025 g, whereas the USDA and Pu Teuy Ae. aegypti produced optimum attractant activation at 0.005 g (72.6% and 58.9%, respectively) without significant difference within species (p > 0.05). In parallel control assays, Cx. quinquefasciatus was significantly attracted to 1 g of dry ice (carbon dioxide) (76%) more than Ae. aegypti (USDA) (12.2%). The HITSS was originally designed to measure three chemical actions to sublethal concentrations of chemicals by mosquitoes: toxicity and the two primary behavior avoidance responses (contact excitation and spatial repellency). These findings demonstrate that the HITSS assay, with only minor modifications, allows comparison screening of candidate compounds as potential attractants for anemotactic responses under laboratory-controlled conditions. Further investigations will be required to equate measurements obtained from controlled laboratory assays to more varied field conditions for attracting natural mosquito populations.

8.
J Econ Entomol ; 113(1): 353-366, 2020 02 08.
Artículo en Inglés | MEDLINE | ID: mdl-31586445

RESUMEN

This study examined the presence of insecticide resistance in different developmental stages (adults, first instars, and eggs) of the tropical bed bug, Cimex hemipterus (F.) using several insecticide formulations. Adults and first instars of five strains (Queensland, Kuala Lumpur, Bukit Mertajam, Saujana, and Krystal Point) were evaluated using the surface contact method and compared with a susceptible strain (Monheim) of the common bed bug Cimex lectularius L. The insecticide formulations were used at their label rates in this study: Tandem (thiamethoxam [11.6%], lambda-cyhalothrin [3.5%]) at 183.96 mg/m2; Temprid SC (imidacloprid [21%], beta-cyfluthrin [10.5%]) at 106.13 mg/m2; Sumithion 20CS (fenitrothion [20%]) at 250 mg/m2; Pesguard FG161 (d-tetramethrin [4.4%], cyphenothrin [13.2%]) at 110 mg/m2; and Sumithrin 10SEC (d-phenothrin [10%]) at 100 mg/m2. Results showed a very high level of resistance to Pesguard FG161 (388.3 to >605.0 times) and Sumithrin (302.9 to >365.5 times) in all adults of the strains tested, whereas low to high levels of resistance were registered for Tandem (1.4-4.7 times), Temprid (7.3-16.7 times), and Sumithion (1.2-14.6 times) for adults of all bed bug strains. For first instars, resistance to the former two formulations were high to very high (31.4-118.1 times). In contrast, they showed lower resistance to Tandem, Temprid, and Sumithion (1.0-10.2 times). An immersion method used to test on bed bug eggs found high to very high resistance toward all tested formulations. Results demonstrate that the resistance level varies between bed bug developmental stages.


Asunto(s)
Chinches/efectos de los fármacos , Infestaciones Ectoparasitarias , Insecticidas/farmacología , Animales , Resistencia a los Insecticidas/efectos de los fármacos , Queensland
9.
Nat Mater ; 18(7): 685-690, 2019 07.
Artículo en Inglés | MEDLINE | ID: mdl-31133731

RESUMEN

Symmetry breaking is a fundamental concept that prevails in many branches of physics1-5. In magnetic materials, broken inversion symmetry induces the Dzyaloshinskii-Moriya interaction (DMI), which results in fascinating physical behaviours6-14 with the potential for application in future spintronic devices15-17. Here, we report the observation of a bulk DMI in GdFeCo amorphous ferrimagnets. The DMI is found to increase linearly with an increasing thickness of the ferrimagnetic layer, which is a clear signature of the bulk nature of DMI. We also found that the DMI is independent of the interface between the heavy metal and ferrimagnetic layer. This bulk DMI is attributed to an asymmetric distribution of the elemental content in the GdFeCo layer, with spatial inversion symmetry broken throughout the layer. We expect that our experimental identification of a bulk DMI will open up additional possibilities to exploit this interaction in a wide range of materials.

10.
Sci Rep ; 9(1): 6500, 2019 04 24.
Artículo en Inglés | MEDLINE | ID: mdl-31019205

RESUMEN

The insect male accessory gland (MAG) is an internal reproductive organ responsible for the synthesis and secretion of seminal fluid components, which play a pivotal role in the male reproductive strategy. In many species of insects, the effective ejaculation of the MAG products is essential for male reproduction. For this purpose, the fruit fly Drosophila has evolved binucleation in the MAG cells, which causes high plasticity of the glandular epithelium, leading to an increase in the volume of seminal fluid that is ejaculated. However, such a binucleation strategy has only been sporadically observed in Dipteran insects, including fruit flies. Here, we report the discovery of binucleation in the MAG of the common bed bug, Cimex lectularius, which belongs to hemimetabolous Hemiptera phylogenetically distant from holometabolous Diptera. In Cimex, the cell morphology and timing of synchrony during binucleation are quite different from those of Drosophila. Additionally, in Drosophila, the position of the two nuclei in the adult stage changes as a result of the mating history or the nutrient conditions; however, it remains stable in Cimex. These differences suggest that binucleation in the Cimex MAG plays a unique role in the male reproductive system that is distinct from that of Drosophila.


Asunto(s)
Chinches/crecimiento & desarrollo , Drosophila/crecimiento & desarrollo , Genitales Masculinos/crecimiento & desarrollo , Estadios del Ciclo de Vida/fisiología , Animales , Chinches/anatomía & histología , Chinches/citología , Drosophila/anatomía & histología , Drosophila/citología , Genitales Masculinos/anatomía & histología , Genitales Masculinos/citología , Masculino , Reproducción/fisiología , Especificidad de la Especie
11.
Nat Nanotechnol ; 14(3): 232-236, 2019 03.
Artículo en Inglés | MEDLINE | ID: mdl-30664756

RESUMEN

In the presence of a magnetic field, the flow of charged particles in a conductor is deflected from the direction of the applied force, which gives rise to the ordinary Hall effect. Analogously, moving skyrmions with non-zero topological charges and finite fictitious magnetic fields exhibit the skyrmion Hall effect, which is detrimental for applications such as skyrmion racetrack memory. It was predicted that the skyrmion Hall effect vanishes for antiferromagnetic skyrmions because their fictitious magnetic field, proportional to net spin density, is zero. Here we investigate the current-driven transverse elongation of pinned ferrimagnetic bubbles. We estimate the skyrmion Hall effect from the angle between the current and the bubble elongation directions. The angle and, hence, the skyrmion Hall effect vanishes at the angular momentum compensation temperature where the net spin density vanishes. Furthermore, our study establishes a direct connection between the fictitious magnetic field and the spin density.

12.
Sensors (Basel) ; 18(9)2018 Sep 13.
Artículo en Inglés | MEDLINE | ID: mdl-30217076

RESUMEN

As a large amount of stream data are generated through sensors over the Internet of Things environment, studies on complex event processing have been conducted to detect information required by users or specific applications in real time. A complex event is made by combining primitive events through a number of operators. However, the existing complex event-processing methods take a long time because they do not consider similarity and redundancy of operators. In this paper, we propose a new complex event-processing method considering similar and redundant operations for stream data from sensors in real time. In the proposed method, a similar operation in common events is converted into a virtual operator, and redundant operations on the same events are converted into a single operator. The event query tree for complex event detection is reconstructed using the converted operators. Through this method, the cost of comparison and inspection of similar and redundant operations is reduced, thereby decreasing the overall processing cost. To prove the superior performance of the proposed method, its performance is evaluated in comparison with existing methods.

13.
Sci Rep ; 7(1): 3660, 2017 06 16.
Artículo en Inglés | MEDLINE | ID: mdl-28623295

RESUMEN

Unidirectional motion of magnetic structures such as the magnetic domain and domain walls is a key concept underlying next-generation memory and logic devices. As a potential candidate of such unidirectional motion, it has been recently demonstrated that the magnetic bubblecade-the coherent unidirectional motion of magnetic bubbles-can be generated by applying an alternating magnetic field. Here we report the optimal configuration of applied magnetic field for the magnetic bubblecade. The tilted alternating magnetic field induces asymmetric expansion and shrinkage of the magnetic bubbles under the influence of the Dzyaloshinskii-Moriya interaction, resulting in continuous shift of the bubbles in time. By examining the magnetic bubblecade in Pt/Co/Pt films, we find that the bubblecade speed is sensitive to the tilt angle with a maximum at an angle, which can be explained well by a simple analytical form within the context of the domain-wall creep theory. A simplified analytic formula for the angle for maximum speed is then given as a function of the amplitude of the alternating magnetic field. The present results provide a useful guideline of optimal design for magnetic bubblecade memory and logic devices.

14.
Sci Rep ; 7: 45498, 2017 03 31.
Artículo en Inglés | MEDLINE | ID: mdl-28361907

RESUMEN

The Dzyaloshinskii-Moriya interaction (DMI) in magnetic objects is of enormous interest, because it generates built-in chirality of magnetic domain walls (DWs) and topologically protected skyrmions, leading to efficient motion driven by spin-orbit torques. Because of its importance for both potential applications and fundamental research, many experimental efforts have been devoted to DMI investigation. However, current experimental probing techniques cover only limited ranges of the DMI strength and have specific sample requirements. Thus, there are no versatile methods to quantify DMI over a wide range of values. Here, we present such an experimental scheme, which is based on the angular dependence of asymmetric DW motion. This method can be used to determine values of DMI much larger than the maximum strength of the external magnetic field strength, which demonstrates that various DMI strengths can be quantified with a single measurement setup. This scheme may thus prove essential to DMI-related emerging fields in nanotechnology.

15.
J Econ Entomol ; 110(3): 1179-1186, 2017 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-28334370

RESUMEN

The climbing abilities of two bed bug species, Cimex lectularius L. and Cimex hemipterus (F.), were determined by evaluating their escape rates from smooth surface pitfall traps using four commercial bed bug monitors (Verifi Bed Bug Detector, ClimbUp Insect Interceptor, BlackOut Bed Bug Detector, and SenSci Volcano Bed Bug Detector). All detectors were used in the absence of lures or attractants. Unlike C. lectularius, adult C. hemipterus were able to escape from all traps. On the other hand, no or a low number nymphs of both species escaped, depending on the evaluated traps. Examination of the vertical friction force of adults of both species revealed a higher vertical friction force in C. hemipterus than in C. lectularius. Scanning electron microscope micrograph observation on the tibial pad of adult bed bugs of C. hemipterus showed the presence of a greater number of tenent hairs on the tibial pad than on that of adult C. lectularius. No tibial pad was found on the fourth and fifth instars of both species. Near the base of the hollow tenent hairs is a glandular epithelium that is better developed in adult C. hemipterus than in adult C. lectularius. This study highlights significant morphological differences between C. lectularius and C. hemipterus, which may have implications in the monitoring and management of bed bug infestations.


Asunto(s)
Chinches/fisiología , Control de Insectos , Animales , Chinches/anatomía & histología , Chinches/crecimiento & desarrollo , Chinches/ultraestructura , Fenómenos Biomecánicos , Extremidades/anatomía & histología , Femenino , Masculino , Microscopía Electrónica de Rastreo , Actividad Motora , Ninfa/anatomía & histología , Ninfa/crecimiento & desarrollo , Ninfa/fisiología , Ninfa/ultraestructura , Especificidad de la Especie
16.
Sensors (Basel) ; 14(7): 11825-43, 2014 Jul 04.
Artículo en Inglés | MEDLINE | ID: mdl-24999716

RESUMEN

In this paper, a 120 frames per second (fps) low noise CMOS Image Sensor (CIS) based on a Two-Step Single Slope ADC (TS SS ADC) and column self-calibration technique is proposed. The TS SS ADC is suitable for high speed video systems because its conversion speed is much faster (by more than 10 times) than that of the Single Slope ADC (SS ADC). However, there exist some mismatching errors between the coarse block and the fine block due to the 2-step operation of the TS SS ADC. In general, this makes it difficult to implement the TS SS ADC beyond a 10-bit resolution. In order to improve such errors, a new 4-input comparator is discussed and a high resolution TS SS ADC is proposed. Further, a feedback circuit that enables column self-calibration to reduce the Fixed Pattern Noise (FPN) is also described. The proposed chip has been fabricated with 0.13 µm Samsung CIS technology and the chip satisfies the VGA resolution. The pixel is based on the 4-TR Active Pixel Sensor (APS). The high frame rate of 120 fps is achieved at the VGA resolution. The measured FPN is 0.38 LSB, and measured dynamic range is about 64.6 dB.

17.
J Urol ; 182(4 Suppl): 1849-53, 2009 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-19692076

RESUMEN

PURPOSE: A decreased percent of differential function is a common indication for infant pyeloplasty but there is no recognized fetal ultrasound parameter to predict this deficit. We determined whether there is a correlation between fetal pyelectasis and the newborn percent differential function that may enhance prenatal counseling and guide postnatal evaluation. MATERIALS AND METHODS: Our database was queried for fetal and newborn measures with fetal pyelectasis on ultrasound and the percent of differential function on renal scintigraphy. Fetal pyelectasis data were stratified by estimated gestational age and the percent of differential function. The affected cohort was defined as having 35% or less differential function and the unaffected cohort was defined as having greater than 35%. The Wilcoxon 2-sample test was used for statistical analysis with logistic regression to generate estimated probability models of a decreased percent of differential function vs mm fetal pyelectasis. RESULTS: A total of 831 cases had fetal and newborn ultrasound data available with a total of 229 renal scans identified. Of the 229 cases 36 (16%) had 35% or less differential function on scintigraphy. At estimated gestational age 33 weeks or less the affected cohort had 8 mm greater pyelectasis than the unaffected cohort (OR 1.2, p <0.0001). At estimated gestational age greater than 33 weeks the affected cohort had 4 mm greater pyelectasis than the unaffected cohort (OR 1.07, p <0.07). Subgroup analysis before 33 weeks of estimated gestational age showed similar significance (OR >1, p

Asunto(s)
Pelvis Renal/diagnóstico por imagen , Pelvis Renal/patología , Riñón/diagnóstico por imagen , Riñón/fisiopatología , Ultrasonografía Prenatal , Consejo , Dilatación Patológica , Humanos , Recién Nacido , Pronóstico , Cintigrafía
18.
BJU Int ; 104(3): 304-9, 2009 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-19239451

RESUMEN

OBJECTIVE: To compare the outcomes between patients with stage T1a/b with those of patients with T1c cancer of the prostate treated with radical retropubic prostatectomy (RRP), as the appropriate management of clinical stage T1a/b prostate cancer is subject to debate; although many patients are managed expectantly, some have adverse pathological features suggesting that more active treatment might be beneficial. PATIENTS AND METHODS: From 1983 to 2003, 3478 men had RRP by one surgeon. From this group, we retrospectively identified 29 men with clinical stage T1a and 83 with clinical stage T1b disease. Using statistical analysis we compared the treatment outcomes of these patients with those of 1774 men with clinical stage T1c disease. RESULTS: Men with T1a/b disease had a significantly lower preoperative prostate-specific antigen (PSA) level, a greater proportion with organ-confined disease, and a lower mean/median prostatectomy Gleason score than those with T1c disease. Also, men with T1a/b disease were less likely to be potent before surgery, although the frequency of recovery of potency was similar among all groups. On multivariate analysis with age, year of surgery, PSA level and Gleason score, there was no statistical difference in the rates of biochemical recurrence and the 10-year overall survival rates. However, patients with T1b disease had a significantly lower cancer-specific survival. CONCLUSIONS: T1a and T1b prostate cancer can be associated with aggressive pathological features and have a similar rate of progression as clinical stage T1c disease. That notwithstanding, most patients in the study were cured with RRP and had favourable long-term functional outcomes.


Asunto(s)
Prostatectomía/métodos , Neoplasias de la Próstata/patología , Neoplasias de la Próstata/cirugía , Anciano , Humanos , Masculino , Persona de Mediana Edad , Análisis Multivariante , Estadificación de Neoplasias , Pronóstico , Antígeno Prostático Específico/metabolismo , Neoplasias de la Próstata/mortalidad , Estudios Retrospectivos , Resultado del Tratamiento
19.
Biotechnol Bioeng ; 95(5): 804-11, 2006 Dec 05.
Artículo en Inglés | MEDLINE | ID: mdl-16933322

RESUMEN

We report the activity, stability, and reusability of enzyme-carbon nanotube conjugates in aqueous solutions. A variety of enzymes were covalently attached to oxidized multi-walled carbon nanotubes (MWNTs). These conjugates were soluble in aqueous buffer, retained a high fraction of their native activity, and were stable at higher temperatures relative to their solution phase counterparts. Furthermore, the high surface area of MWNTs afforded high enzyme loadings, yet the intrinsic high length of the MWNT led to facile filtration. These water-soluble carbon nanotube-enzyme conjugates represent novel preparations that possess the virtues of both soluble and immobilized enzymes, thus providing a unique combination of useful attributes such as low mass transfer resistance, high activity and stability, and reusability.


Asunto(s)
Enzimas Inmovilizadas/síntesis química , Nanotubos de Carbono/química , Biotransformación , Caspasas Iniciadoras/química , Catálisis , Enzimas Inmovilizadas/aislamiento & purificación , Cinética , Peroxidasas/química , Solubilidad
20.
Korean J Gastroenterol ; 42(4): 303-12, 2003 Oct.
Artículo en Coreano | MEDLINE | ID: mdl-14634350

RESUMEN

BACKGROUND/AIMS: Lamivudine, an oral nucleoside analogue, effectively suppresses hepatitis B virus (HBV) replications and improves liver enzymes as well as liver histology. The aim of this study was to evaluate the effectiveness of lamivudine and the patient-dependent or laboratory variables that predict HBeAg seroconversion. METHODS: We retrospectively analyzed 519 consecutive patients with HBeAg-positive chronic hepatitis B who were treated with lamivudine. The duration of lamivudine therapy was from 6 to 64 months (mean 20 months). RESULTS: The HBeAg seroconversion was achieved in 192 patients (37%). The cumulative HBeAg seroconversion rates were 28% at 12 months, 39% at 24 months, 49% at 36 months, and 53% at 48 months. The predictive factors of lamivudine-induced HBeAg seroconvresion were the changing patterns of quantitative HBeAg level during lamivudine therapy, pretreatment quantitative HBeAg levels, ALT levels, and the duration of lamivudine therapy. One hundred eighty-three patients who had achieved HBeAg seroconversion showed patterns that HBeAg levels were continuously decreased. Therapy was discontinued after HBeAg seroconversion in 121 patients. Sixty-six patients experienced a relapse during the follow-up period (mean 8.9 months). CONCLUSIONS: The continuously decreasing patterns of quantitative HBeAg levels during lamivudine therapy can predict HBeAg seroconversion in clinical settings.


Asunto(s)
Antivirales/uso terapéutico , Hepatitis B Crónica/tratamiento farmacológico , Lamivudine/uso terapéutico , Adolescente , Adulto , Anciano , Femenino , Antígenos e de la Hepatitis B/sangre , Hepatitis B Crónica/virología , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Resultado del Tratamiento
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA